dictyNews Volume 43 Number 05

Published in

· 1 year ago

dictyNews 
Electronic Edition 
Volume 43, number 5 
March 17, 2017 

Please submit abstracts of your papers as soon as they have been 
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========= 
Abstracts 
========= 

 
Protein Kinase A regulates the Ras, Rap1, and TORC2 pathways in  
response to the chemoattractant cAMP in Dictyostelium 

Margarethakay Scavello, Alexandra R. Petlick, Ramya Ramesh,  
Valery F. Thompson, Pouya Lotfi, and Pascale G. Charest. 

 
Journal of Cell Science, in press 

Efficient directed migration requires tight regulation of  
chemoattractant signal transduction pathways in both space and  
time, but the mechanisms involved in such regulation are not  
well understood. Here, we investigated the role of Protein  
Kinase A (PKA) in controlling signaling of the chemoattractant  
cAMP in Dictyostelium. We found that cells lacking PKA display  
severe chemotaxis defects, including impaired directional sensing.  
Although PKA is an important regulator of developmental gene  
expression, including the cAMP receptor cAR1, our studies using  
exogenously expressed cAR1 in cells lacking PKA, cells lacking  
adenylyl cyclase A (ACA), and cells treated with the PKA-selective  
pharmacological inhibitor H89, suggest that PKA controls  
chemoattractant signal transduction, in part, through the  
regulation of RasG, Rap1, and TORC2. As these pathways control  
the ACA-mediated production of intracellular cAMP, they lie  
upstream of PKA in this chemoattractant signaling network.  
Consequently, we propose that the PKA-mediated regulation of  
the upstream RasG, Rap1, and TORC2 signaling pathways is part  
of a negative feedback mechanism controlling chemoattractant  
signal transduction during Dictyostelium chemotaxis. 

 
submitted by: Pascale Charest [pcharest@email.arizona.edu] 
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[End dictyNews, volume 43, number 5]